Working with Grumpy Camels

Gabriel Scherer

OCaml Paris Meeting, May 21st


The OCaml implementation is a free software project

(I'm talking on the compiler, libraries and tools distributed together on

The usual advice for contribution:

Core maintainers

They historically come from a specific INRIA team
... but are now spread among continents and industries!

Most parts of the codebase have one or two specific maintainers.
They react to bug reports, and their opinion on change proposals is generally respected.

% git shortlog -n -s HEAD~1000... # Oct. 2011
  305  Damien Doligez
  215  Alain Frisch
  155  Jacques Garrigue
   81  Wojciech Meyer
   78  Xavier Leroy
   46  Fabrice Le Fessant
   38  Benedikt Meurer
   35  Pierre Weis
   29  Xavier Clerc
   26  Jérémie Dimino
   23  Jonathan Protzenko
   15  Gabriel Scherer
   11  Hongbo Zhang
    5  Maxence Guesdon
    2  Luc Maranget

The Bugtracker

Most of the development activity goes through the bugtracker.


(There is a private development mailing-list, mostly review requests for larger changes from maintainers.)


We already do have a lot of external contributors on the bugtracker!

Specifics: language maintainers are conservative by experience

Benevolent part-time hobby

Maintainers get no professional recognition for their work.


Researchers rarely get credit for implementing software.
Never for maintaining it.


Think of this as a after-work hobby.

Long-time responsability

Maintainers are in charge for a long time.


First OCaml commit around 1995.


Caml as a language starts around 1985.


Stuff we add now will still be there in 2025.

Mistakes are forever

Very strict backward-compatibility requirements for the language (and distributed library).


Breaking changes are not accepted.


Changes that don't feel right are suspicious.

Life in the bug tracker

What's in there

Bugs: stuff that is broken. Simple, objective. We like bug reports.

You can help by reporting them, adding information to the report (eg. other related cases that are also broken), suggesting patches to fix it, or reviewing or suggested patches.


Feature requests. Easy to propose, hard and stressful to evaluate.

Most of the time feature requests overlap with existing or desired features, and don't add enough value to be worth it.


Optimizations: changes that allegedly make program faster.

Most of the time, optimizations do great on a well-chosen microbenchmark, but have a neglectible effects in real programs.

We don't want to make the compiler more complex unless the gain is real.

OCamlbuild notice

Some areas of the distribution are younger, so there is more "free space" for fixes and feature contributions.


Bugfixes and contributions for OCamlbuild are desirable and welcome.


There are numerous feature requests submitted already. Go see if there is something you want to help implement.


(It's fine if you use another build system.)


Bugtracker summary

There are several ways one can contribute to the development of the OCaml distribution. They go through the bugtracker:

Junior contributor? Follow the bugtracker.

Or outside the distribution!

OCaml distribution is a small part of the OCaml ecosystem. There are a lot of (better?) ways to contribute. For example:

Thanks. Questions?